Electronic device

ABSTRACT

An electronic device includes a chip component and a metal terminal. The chip component has an element body where internal electrodes are laminated inside and a terminal electrode formed outside the element body and connected with end parts of the internal electrodes. The metal terminal is connected with the terminal electrode of the chip component. The metal terminal includes an electrode face portion and a mount portion. The electrode face portion is arranged correspondingly with an end surface of the terminal electrode. The mount portion is mounted on a mount surface. The electrode face portion is provided with an opening portion so that a part of the terminal electrode corresponding with at least a part of the internal electrodes is exposed to the outside.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an electronic device with a terminal.

2. Description of the Related Art

In addition to a normal chip component that is solely directly mounted on a board, as shown in Patent Document 1 for example, a chip component attached with a metal terminal is proposed as an electronic device, such as a ceramic capacitor.

It is reported that the electronic device attached with a metal terminal after being mounted has a reduction effect on a deformation stress that travels from a board to a chip component and a protection effect on a chip component from impacts or so. Thus, the electronic device attached with a metal terminal is used in a field where durability, reliability, and the like are required.

In conventional electronic devices with a metal terminal, however, a terminal electrode of a chip component and a metal terminal are joined by only a solder, and there is a problem with the joint. For example, the soldering operation needs to be conducted while the terminal electrode of the chip component and the metal terminal are being positioned. In particular, when a plurality of chip components is soldered to a pair of metal terminals, this operation is complicated, and the joint reliability may decrease.

When the entire end surface of the terminal electrode of the chip component is soldered to the metal terminal, a joint strength between the metal terminal and the terminal electrode improves, but the metal terminal is hard to be deformed elastically. In addition, a vibration from the chip component easily travels to a board or so, and a so-called acoustic noise may occur. Moreover, when used in a high temperature environment, an environment with a large temperature change, or the like, a joint between the chip component and the metal terminal may be released due to a difference in thermal expansion coefficient between a solder and the metal terminal.

Incidentally, an electronic device where a chip component is connected with a metal terminal by engagement arm portions is proposed. This structure is expected to demonstrate a prevention effect on an acoustic noise phenomenon or so. In this structure, it is conceivable that a joint strength between the chip component and the metal terminal is improved. In this case, however, the prevention effect on an acoustic noise phenomenon may decrease.

-   Patent Document 1: JP 2000-235932 A

SUMMARY OF THE INVENTION

The present invention has been achieved under such circumstances. It is an object of the invention to provide an electronic device that is capable of securely and firmly connecting between a chip component and a metal terminal and is excellent in a prevention effect on an acoustic noise phenomenon.

To achieve the above object, the electronic device according to the present invention is an electronic device comprising:

a chip component having an element body where internal electrodes are laminated inside and a terminal electrode formed outside the element body and connected with end parts of the internal electrodes; and

a metal terminal connected with the terminal electrode of the chip component,

wherein the metal terminal comprises:

an electrode face portion arranged correspondingly with an end surface of the terminal electrode; and

a mount portion mounted on a mount surface, and

the electrode face portion is provided with an opening portion so that a part of the terminal electrode corresponding with at least a part of the internal electrodes is exposed to the outside.

In the electronic device according to the present invention, the electrode face portion is provided with the opening portion. In the opening portion, no vibration travels from the chip component to the metal terminal. In particular, a vibration is easily generated in a part of the chip component where the internal electrodes are laminated via the dielectric layers due to electrostrictive phenomenon. In the present invention, however, the vibration can be effectively prevented from traveling to the mount board in the opening portion near the mount surface. Thus, an acoustic noise phenomenon can be prevented effectively.

Preferably, the terminal electrode of the chip component is connected with the metal terminal so that plane directions of the internal electrodes are arranged substantially vertically to the mount surface. This structure can effectively prevent an electrostrictive vibration of the internal electrodes from traveling to the mount board.

Preferably, the metal terminal further comprises a holding portion holing the chip component,

a connection member connecting between the electrode face portion and the end surface of the terminal electrode exists therebetween in a joint region within a first predetermined height,

the electrode face portion is provided with the opening portion between a periphery portion of the joint region and the mount portion, and

a non-joint region where the connection member does not exist between the electrode face portion and the end surface of the terminal electrode exists in a non-opening region of the electrode face portion within a second predetermined height corresponding with the opening portion.

When the holding portion of the metal terminal holds the chip component and the metal terminal and the chip component are connected with each other in the joint region within a predetermined range by the connection member, such as a solder, the metal terminal and the chip component can be joined securely and firmly. Incidentally, the connection member is not limited to a solder, and may be a conductive adhesive or so.

When a non-joint region where the connection member does not exist between the electrode face portion and the end surface of the terminal electrode exists in a non-opening region of the electrode face portion within a second predetermined height corresponding with the opening portion, the electrode face portion of the metal terminal can be freely elastically deformed without being disturbed, and stress is reduced in the non-joint region. This favorably maintains an elastic property of the holding portion continuing to the non-joint region, and the chip component can be favorably held by the holding portion. In addition, the metal terminal is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

Preferably, the electrode face portion is provided with the opening portion so that a vicinity of an end part of the terminal electrode is exposed to the outside. In this structure, an electrostrictive vibration of the internal electrodes can be prevented from traveling to the metal terminal on the side close to the mount portion.

Preferably, a length of a part of the internal electrodes corresponding with a part of the terminal electrode exposed by the opening portion is 1/20 or more of a total length of the internal electrode. This structure improves a prevention effect on an electrostrictive vibration from traveling to the metal terminal in the opening portion. Incidentally, a length of the internal electrodes corresponding with a part of the terminal electrode exposed by the second through hole is preferably ½ or less of a total length of the internal electrode. This is for improving a joint strength between the electrode face portion of the metal terminal and the terminal electrode of the chip component.

A space whose thickness is substantially equal to a thickness of the connection member may exist between the electrode face portion and the end surface of the terminal electrode in the non-joint region. The space enables the electrode face portion of the non-joint region to be freely elastically deformed without any disturbance from the metal terminal.

End surfaces of terminal electrodes of a plurality of the chip components may be joined side by side with the electrode face portion by a plurality of joint regions, and the non-joint region is preferably also formed between the joint regions adjacent to each other. In this structure, a pair of the metal terminals can easily connect a plurality of the chip components, and an acoustic noise phenomenon can be prevented due to the existence of the non-joint region existing between the chip components.

Preferably, the holding portion is formed on the side of the mount portion of the opening portion. In this structure, an electrostrictive vibration of the internal electrodes can be prevented from traveling to the metal terminal on the side close to the mount portion. The holding portion is hard to be affected by the electrostrictive vibration and can securely hold the chip component.

Preferably, the holding portion is formed by being bent from an opening periphery of the opening portion. In this structure, the opening portion and the holding portion can be easily formed. In this structure, the opening portion and the holding portion are arranged close to each other, and a vibration transmission from the chip component to the metal terminal can be prevented more effectively.

The joint region may be provided with a through hole going through the front and back surfaces of the electrode face portion. In this structure, an application state of the connection member in the joint region can be observed from outside via the through hole. In this structure, bubbles contained in the connection member, such as a solder, can be released via the through hole. This stabilizes the joint even if the amount of the connection member, such as a solder, is small.

In the joint region, a protrusion protruding toward the end surface of the terminal electrode may be formed on the inner surface of the electrode face portion. This structure can easily control an application region of the connection member and the thickness of the joint region. In addition, this structure stabilizes the connection of the connection member even if the amount of the connection member is small.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view showing a ceramic electronic device according to an embodiment of the present invention.

FIG. 2 is a front view of the ceramic electronic device shown in FIG. 1.

FIG. 3A is a left side view of the ceramic electronic device shown in FIG. 1.

FIG. 3B is a left side view of a ceramic electronic device according to a variation of the embodiment shown in FIG. 3A.

FIG. 3C is a left side view of a ceramic electronic device according to another embodiment of the present invention.

FIG. 3D is a left side view of a ceramic electronic device according to further another embodiment of the present invention.

FIG. 3E is a left side view of a ceramic electronic device according to further another embodiment of the present invention.

FIG. 3F is a left side view of a ceramic electronic device according to further another embodiment of the present invention.

FIG. 4 is a top view of the ceramic electronic device shown in FIG. 1.

FIG. 5 is a bottom view of the ceramic electronic device shown in FIG. 1.

FIG. 6 is a cross sectional view vertical to the Y-axis of the ceramic electronic device shown in FIG. 1.

FIG. 7 is a schematic perspective view showing a ceramic electronic device according to another embodiment of the present invention.

FIG. 8 is a front view of the ceramic electronic device shown in FIG. 7.

FIG. 9 is a left side view of the ceramic electronic device shown in FIG. 7.

FIG. 10 is a top view of the ceramic electronic device shown in FIG. 7.

FIG. 11 is a bottom view of the ceramic electronic device shown in FIG. 7.

FIG. 12 is a schematic perspective view showing the ceramic electronic device according to the variation of the embodiment shown in FIG. 7.

FIG. 13 is a schematic perspective view showing the ceramic electronic device according to the variation of the embodiment shown in FIG. 12.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the present invention is described based on embodiments shown in figures.

First Embodiment

FIG. 1 is a schematic perspective view showing a capacitor 10 as an electronic device according to First Embodiment of the present invention. The capacitor 10 has capacitor chips 20 as chip components and a pair of metal terminals 30 and 40. The capacitor 10 according to First Embodiment has the two capacitor chips 20, but the capacitor 10 may have a single capacitor chip 20 or any plural capacitor chips 20.

Incidentally, each embodiment is described with a capacitor where the capacitor chips 20 are equipped with the metal terminals 30 and 40, but the ceramic electronic device of the present invention is not limited to the capacitor, and may be a chip component other than capacitors equipped with the metal terminals 30 and 40.

In the figures, the X-axis, the Y-axis, and the Z-axis are vertical to each other, the X-axis is parallel to a direction where the capacitor chips 20 are arranged as shown in FIG. 1, the Z-axis corresponds with a height direction of the capacitor 10 from a mount surface, and the Y-axis corresponds with a direction where a pair of terminal electrodes 22 and 24 of the chips 20 is mutually arranged on the opposite side.

The capacitor chips 20 have an approximately rectangular parallelepiped shape, and each of the two capacitor chips 20 has approximately the same shape and size. As shown in FIG. 2, the capacitor chips 20 have a pair of chip end surfaces facing each other, and the pair of chip end surfaces consists of a first end surface 20 a and a second end surface 20 b. As shown in FIG. 1, FIG. 2, and FIG. 4, the first and second end surfaces 20 a and 20 b have an approximately rectangular shape. In four sides constituting each rectangular of the first and second end surfaces 20 a and 20 b, a pair of longer sides is chip first sides 20 g (see FIG. 2), and a pair of shorter sides is chip second sides 20 h (see FIG. 3A).

The capacitor chips 20 are arranged so that the first end surfaces 20 a and the second end surfaces 20 b are vertical to a mount surface, in other words, the chip third sides 20 j of the capacitor chips 20 connecting between the first end surfaces 20 a and the second end surfaces 20 b are parallel to the mount surface of the capacitor 10. Incidentally, the mount surface of the capacitor 10 is a surface attached with the capacitor 10 by solder or so and facing mount portions 38 and 48 of the metal terminals 30 and 40 mentioned below.

When comparing a length L1 of the chip first side 20 g shown in FIG. 2 and a length L2 of the chip second side 20 h shown in FIG. 4, the chip second side 20 h is shorter than the chip first side 20 g (L1>L2). The chip first side 20 g and the chip second side 20 h have any length ratio, but L2/L1 is about 0.3 to 0.7, for example.

The capacitor chips 20 are arranged so that the chip first sides 20 g are vertical to the mount surface as shown in FIG. 2, and that the chip second sides 20 h are parallel to the mount surface as shown in FIG. 4. In the first to fourth side surfaces 20 c to 20 f, which are the four chip side surfaces connecting the first end surfaces 20 a and the second end surfaces 20 b, the first and second side surfaces 20 c and 20 d, whose areas are large, are arranged vertically to the mount surface, and the third and fourth side surfaces 20 e and 20 f, whose areas are smaller than those of the first and second side surfaces 20 and 20 d, are arranged in parallel to the mount surface. The third side surfaces 20 e are upper side surfaces facing the opposite direction to the mount portions 38 and 48 below, and the fourth sides surfaces 20 f are lower side surfaces facing the mount portions 38 and 48.

As shown in FIG. 1, FIG. 2, and FIG. 4, first terminal electrodes 22 of the capacitor chips 20 are formed to reach from the first end surfaces 20 a to a part of the first to fourth side surfaces 20 c to 20 f Thus, the first terminal electrode 22 has a part arranged on the first end surface 20 a and a part arranged on the first to fourth side surfaces 20 c and 20 f.

The second terminal electrodes 24 of the capacitor chips 20 are formed to reach from the second end surfaces 20 b to another part of the first to fourth side surfaces 20 c to 20 f (a different part from the part where the first terminal electrodes 22 reach). Thus, the second terminal electrode 24 has a part arranged on the second end surface 20 b and a part arranged on the first to fourth side surfaces 20 c to 20 f (see FIG. 1, FIG. 2, and FIG. 4). The first terminal electrodes 22 and the second terminal electrodes 24 are arranged with a predetermined distance on the first to fourth side surfaces 20 c to 20 f.

As shown in FIG. 6, which schematically shows internal structures of the capacitor chips 20, the capacitor chips 20 are a multilayer capacitor where internal electrode layers 26 and dielectric layers 28 are laminated. In the internal electrode layers 26, internal electrode layers 26 connected with the first terminal electrodes 22 and internal electrode layers 26 connected with the second terminal electrodes 24 are laminated alternately by sandwiching the dielectric layers 28.

As shown in FIG. 6, the internal electrode layers 26 of the capacitor chips 20 have a lamination direction that is parallel to the X-axis and vertical to the Y-axis. That is, the internal electrode layers 26 shown in FIG. 6 are arranged in parallel to the plane of the Z-axis and the Y-axis and vertically to the mount surface.

The dielectric layers 28 of the capacitor chips 20 are composed of any dielectric material, such as calcium titanate, strontium titanate, barium titanate, and a mixture thereof. Each of the dielectric layers 28 has any thickness, but normally has a thickness of several μm to several hundred μm. In the present embodiment, each of the dielectric layers 28 preferably has a thickness of 1.0 to 5.0 μm. The dielectric layers 28 preferably have a main component of barium titanate, which can increase capacitance of capacitors.

The internal electrode layers 26 contain any conductive material, but may contain a comparatively inexpensive base metal when the dielectric layers 28 are composed of a reduction resistant material. The base metal is preferably Ni or a Ni alloy. The Ni alloy is preferably an alloy of Ni and one or more elements of Mn, Cr, Co, and Al, and preferably contains Ni at 95 wt % or more. Incidentally, Ni or the Ni alloy may contain various fine components, such as P, at about 0.1 wt % or less. The internal electrode layers 26 may be formed using a commercially available electrode paste. Each of the internal electrode layers 26 has a thickness appropriately determined based on usage or so.

The first and second terminal electrodes 22 and 24 are also composed of any material. The first and second terminal electrodes 22 and 24 are normally composed of copper, copper alloy, nickel, nickel alloy, or the like, but may be composed of silver, an alloy of silver and palladium. Each of the first and second terminal electrodes 22 and 24 also has any thickness, but normally has a thickness of about 10 to 50 μm. Incidentally, at least one metal film of Ni, Cu, Sn, etc. may be formed on the surfaces of the first and second terminal electrodes 22 and 24.

The capacitor chips 20 have shape and size that are appropriately determined based on object and usage. For example, the capacitor chip 20 has a length (L3 shown in FIG. 2) of 1.0 to 6.5 mm, preferably 3.2 to 5.9 mm, a width (L1 shown in FIG. 2) of 0.5 to 5.5 mm, preferably 1.6 to 5.2 mm, and a thickness (L2 shown in FIG. 4) of 0.3 to 3.5 mm, preferably 0.8 to 3.2 mm. When the capacitor 10 has a plurality of the capacitor chips 20, each of the capacitor chips 20 may have mutually different size and shape.

A pair of the metal terminals 30 and 40 of the capacitor 10 is arranged correspondingly with the first and second end surfaces 20 a and 20 b, which are a pair of chip end surfaces. That is, the first metal terminal 30, which is one of the pair of the metal terminals 30 and 40, is arranged correspondingly with the first terminal electrodes 22, which are one of the pair of the terminal electrodes 22 and 24, and the second metal terminal 40, which is the other of the pair of the metal terminals 30 and 40, is arranged correspondingly with the second terminal electrodes 24, which are the other of the pair of the terminal electrodes 22 and 24.

The first metal terminal 30 has an electrode face portion 36, a plurality of pairs of engagement arm portions (holding portions) 31 a, 31 b, 33 a, and 33 b, and a mount portion 38. The electrode face portion 36 faces the first terminal electrodes 22. The engagement arm portions 31 a, 31 b, 33 a, and 33 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 38 extends from the electrode face portion 36 toward the capacitor chips 20 and is at least partially approximately vertical to the electrode face portion 36.

As shown in FIG. 2, the electrode face portion 36 has a substantially rectangular flat shape having a pair of terminal first sides 36 g approximately parallel to the chip first sides 20 g vertical to the mount surface and a pair of terminal second sides 36 ha and 36 hb approximately parallel to the chip second sides 20 h approximately parallel to the mount surface as shown in FIG. 3A.

As shown in FIG. 3A and FIG. 3B (First Variation), the terminal second sides 36 ha and 36 hb parallel to the mount surface have a length that is several times plus or minus alpha of a length L2 (see FIG. 4) of the chip second sides 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. That is, the electrode face portion 36 has a width in the X-axis that may be equal to, slightly shorter, or slightly longer than a length obtained by multiplying the number and X-axis width of the capacitor chips 20 contained in the capacitor 10 shown in FIG. 3A or a capacitor 200 shown in FIG. 3B.

For example, the capacitor 200 according to First Variation shown in FIG. 3B includes two capacitor chips 20, and terminal second sides 36 ha and 36 hb parallel to a mount surface have a length that is shorter than a double of a length L2 of a chip second side 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. Incidentally, the capacitor 200 is the same as the capacitor 10 shown in FIG. 1 to FIG. 6 except that the chip second sides of the capacitor chips 20 have a length that is longer than a length of the chip second sides 20 h of the capacitor chips 20 according to the embodiment.

On the other hand, the capacitor 10 according to First Embodiment shown in FIG. 3A includes two capacitor chips 20, and the terminal second sides 36 ha and 36 hb parallel to the mount surface have a length that is the same as or slightly longer than a double of a length L2 of the chip second side 20 h arranged in parallel to the terminal second sides 36 ha and 36 hb. As shown in FIG. 3A, a capacitor chip that can be combined with the metal terminals 30 and 40 does not have only one size, and the metal terminals 30 and 40 can constitute a capacitor correspondingly with multiple kinds of capacitor chips 20 having different lengths in the X-axis direction.

The electrode face portion 36 is electrically and mechanically connected with the first terminal electrodes 22 formed on the first end surfaces 20 a facing the electrode face portion 36. For example, the electrode face portion 36 and the first terminal electrodes 22 can be connected with each other by arranging a conductive connection member 50, such as a solder and a conductive adhesive, in a space between the electrode face portion 36 and the first terminal electrodes 22 shown in FIG. 2.

Joint regions 50 a are determined as a region where the connection member 50 joins the electrode face portion 36 and the end surfaces of the first terminal electrodes 22. A non-joint region 50 b is determined as a region where the electrode face portion 36 and the end surfaces of the first terminal electrodes 22 are not joined without the connection member 50, and a space exists between the electrode face portion 36 and the end surfaces of the first terminal electrodes 22. The space between the electrode face portion 36 and the end surfaces of the first terminal electrodes 22 in the non-joint region 50 b has a thickness that is approximately equal to a thickness of the connection member 50. In the present embodiment, the connection member 50 has a thickness that is determined based on a height of protrusions 36 a mentioned below or so. The joint regions 50 a have a height in the Z-axis direction corresponding with a first predetermined height.

In the present embodiment, first through holes 36 b are formed on a part of the electrode face portion 36 facing the first end surfaces 20 a. Two first through holes 36 b are formed correspondingly with the capacitor chips 20 contained in the capacitor 10, but any shape and number of the first through holes 36 b may be formed. In the present embodiment, the first through hole 36 b is formed in an approximately central part of the joint region 50 a.

As shown in FIG. 3A, the joint region 50 a is formed by applying the connection member 50 (see FIG. 2) to initial application regions 50 c respectively positioned both sides of the first through hole 36 b in the Z-axis direction. That is, after the connection member 50 is applied, the joint region 50 a is formed in such a manner that the connection member 50 applied on the initial application regions 50 c spreads out by pushing a heating element from the external surface of the electrode face portion 36 toward the end surface of the chip 20. The non-joint region 50 b is a region where the connection member 50 is not spread out. In the present embodiment, a total area of the non-joint region 50 b between the electrode face portion 36 and the end surfaces of the terminal electrodes 22 in the Y-axis direction is larger than 3/10, preferably ½ to 10, of a total area of the joint regions 50 a.

In the present embodiment, a connection member 50 composed of a solder forms a solder bridge between a periphery of the first through hole 36 b and the first terminal electrode 22, and the electrode face portion 36 and the first terminal electrode 22 can be thereby joined strongly. Moreover, an application state of the connection member 50 in the joint region 50 a can be observed from outside via the first through hole 36 b. Moreover, bubbles contained in the connection member 50, such as a solder, can be released via the first through hole 36 b. This stabilizes the joint even if the amount of the connection member 50, such as a solder, is small.

The electrode face portion 36 is provided with a plurality of protrusions 36 a protruding toward the first end surfaces 20 a of the capacitor chips 20 and touching the first end surfaces 20 a. In addition, the protrusions 36 a may be formed outside the initial application regions 50 c, or the initial application regions 50 c may be positioned between the protrusions 36 a and the first through hole 36 b. Incidentally, the initial application region 50 c may protrude from between the protrusion 36 a and the first through hole 36 b.

The protrusions 36 a reduce a contact area between the electrode face portion 36 and the first terminal electrodes 22. This makes it possible to prevent a vibration generated in the chip capacitors 20 from traveling to the mount board via the first metal terminal portion 30 and prevent an acoustic noise of the ceramic capacitor 10.

The protrusions 36 a are formed around the first through hole 36 b, and the joint region 50 a formed by the spread of the connection member 50, such as a solder, can be thereby adjusted. In the present embodiment, the joint region 50 a has a periphery positioned slightly outside the protrusions 36 a. In particular, as shown in FIG. 1, an lower end part of the joint region 50 a in the Z-axis direction is positioned near an upper opening edge of a second through hole (opening portion) 36 c mentioned below.

In such a capacitor 10, an acoustic noise can be prevented while a connection strength between the electrode face portion 36 and the first terminal electrodes 22 is adjusted in an appropriate range. Incidentally, four protrusions 36 a are formed around one first through hole 36 b in the capacitor 10, but any number and arrangement of the protrusions 36 a may be employed.

The electrode face portion 36 is provided with second through holes (opening portions) 36 c having a periphery portion connected with the lower arm portion 31 b or 33 b, which is one of multiple pairs of the engagement arm portions 31 a, 31 b, 33 a, and 33 b. The second through holes 36 c are positioned closer to the mount portion 38 than the first through holes 36 b. Unlike the first through holes 36 b, the second through holes 36 c are not provided with any connection member, such as a solder. That is, the second through holes 36 c are formed in the non-joint region 50 b.

In the first metal terminal portion 30, non-opening regions 36 c 1 positioned on both sides of the second through holes 36 c in the X-axis direction provided with the lower arm portions 31 b and 33 b supporting the capacitor chips 20 function as the non-joint region 50 b between the non-opening regions 36 c 1 and the terminal electrodes 22 and have an easily defomable shape. It is thereby possible to effectively demonstrate a reduction effect on a stress generated in the capacitor 10 and an absorption effect on a vibration of the capacitor chips 20. Thus, the capacitor 10 having the first metal terminal 30 can favorably prevent an acoustic noise and have a favorable connection reliability with the mount board when being mounted.

The second through holes 36 c have any shape, but preferably have an opening width in the width direction, which is a parallel direction (X-axis direction) to the terminal second sides 36 ha and 36 hb, that is wider than the first through holes 36 b. When the second through holes 36 c have a wide opening width, the first metal terminal 30 can effectively enhance a reduction effect on stress and a prevention effect on acoustic noise. When the first through holes 36 b have an opening width that is narrower than the second through holes 36 c, the connection member does not spread too much. As a result, a connection strength between the capacitor chips 20 and the electrode face portion 36 is prevented from being too strong, and such a capacitor 10 can prevent an acoustic noise.

In the present embodiment, as shown in FIG. 3A, the second through holes 36 c are formed on the electrode face portion 36 so that a part (a part of the lower end parts) of the terminal electrodes 22 corresponding with at least a part including the lower end parts of the internal electrode layers 26 in the Z-axis direction is exposed to the outside between the lower end parts of the joint regions 50 a in the Z-axis direction and the mount portion 38. As shown in FIG. 2, the non-joint region 50 b, where the connection member 50 fails to exist between the electrode face portion 36 and the end surfaces of the terminal electrodes 22, exists in the non-opening region 36 c 1 of the electrode face portion 36 within a height L4 in the Z-axis direction corresponding with the second through holes 36 c (second predetermined height). In the present embodiment, the height L4 in the Z-axis direction corresponding with the second through holes 36 c (second predetermined height) approximately corresponds with a height of the non-joint region 50 b in the Z-axis direction, which is positioned below the joint region 50 a in the Z-axis direction, but may be smaller than a height of the non-joint region 50 b in the Z-axis direction.

In the present embodiment, a length L5 of a part of the internal electrodes 26 (a height in the Z-axis direction) corresponding with a part of the terminal electrodes 22 exposed by the second through holes 36 c is preferably 1/20 or more, more preferably ⅛ to ½, of a total length L6 of the internal electrode 26 in the Z-axis direction shown in FIG. 6. The length L5 of a part of the internal electrodes 26 (a height in the Z-axis direction) corresponding with a part of the terminal electrodes 22 exposed by the second through holes 36 c is equal to or smaller than the height L4 of the second through holes 36 c in the Z-axis direction and is preferably smaller than a height of the joint regions 50 a in the Z-axis direction shown in FIG. 2 (first predetermined height).

In the present embodiment, each of the second through holes 36 c formed in the respective chips 20 has a width in the X-axis direction that is preferably smaller than a width of the respective chips 20 in the X-axis direction, and has a width in the X-axis direction that is preferably ⅙ to ⅚, more preferably ⅓ to ⅔, of a width of each of the chips 20 in the X-axis direction.

In the electrode face portion 36, the second through hole 36 c connected with the lower arm portion 31 b is formed with a predetermined distance in the height direction against the terminal second side 36 hb below connected with the mount portion 38, and a slit 36 d is formed between the second through hole 36 c and the terminal second side 36 hb.

In the electrode face portion 36, the slit 36 d is formed between a connection position of the lower arm portion 31 b positioned near the mount portion 38 with the electrode face portion 36 (a lower side of a periphery portion of the second through hole 36 c) and the terminal second side 36 hb below connected with the mount portion 38. The slits 36 d extend in a parallel direction to the terminal second sides 36 ha and 36 hb. The slits 36 d can prevent a solder used at the time of mounting the capacitor 10 on a mount board from creeping up on the electrode face portion 36 and prevent a formation of a solder bridge connected with the lower arm portions 31 b and 33 b or the first terminal electrodes 22. Thus, the capacitor 10 with the slits 36 d demonstrates a prevention effect on acoustic noise.

As shown in FIG. 1 and FIG. 2, the engagement arm portions 31 a, 31 b, 33 a, and 33 b of the first metal terminal 30 extend from the electrode face portion 36 to the third or fourth side surfaces 20 e or 20 f, which are chip side surfaces of the capacitor chips 20. The lower arm portion 31 b (or lower arm portion 33 b), which is one of the engagement arm portions 31 a, 31 b, 33 a, and 33 b, is formed by being bent from the lower periphery portion of the second through hole 36 c in the Z-axis direction formed on the electrode face portion 36.

The upper arm portion 31 a (or upper arm portion 33 a), which is another one of the engagement arm portions 31 a, 31 b, 33 a, and 33 b, is formed by being bent from the terminal second side 36 ha at the upper part of the electrode face portion 36 (positive side of the Z-axis direction).

As shown in FIG. 1, the electrode face portion 36 has a plate body part 36 j and a terminal connection part 36 k. The plate body part 36 j faces the first end surfaces 20 a of the capacitor chips 20 and is positioned at a height overlapping with the first end surfaces 20 a. The terminal connection part 36 k is positioned below the plate body part 36 j and is located at a position connecting between the plate body part 36 j and the mount portion 38.

The second through holes 36 c are formed so that their periphery portions range the plate body part 36 j and the terminal connection part 36 k. The lower arm portions 31 b and 33 b extend from the terminal connection part 36 k. That is, bases of the lower arm portions 31 b and 33 b are connected with lower sides (opening edges near the mount portion 38) of approximately rectangular periphery portions of the second through holes 36 c.

The lower arm portions 31 b and 33 b extend from the bases toward inside in the Y-axis direction (toward the central parts of the chips 20) while being bent, touch the fourth side surfaces 20 f of the capacitor chips 20, and support the capacitor chips 20 from below (see FIG. 2). Incidentally, the lower arm portions 31 b and 33 b may tilt upward in the Z-axis direction from the lower sides of the periphery portions of the second through holes 36 c before the chips 20 are attached. This is for enabling the lower arm portions 31 b and 33 b to touch the fourth side surfaces 20 f of the chips 20 due to the resilience of the lower arm portions 31 b and 33 b.

Lower edges (chip second sides 20 h below) of the first end surfaces 20 a of the capacitor chips 20 are positioned slightly above the lower sides of the periphery portions of the second through holes 36 c, which are the bases of the lower arm portions 31 b and 33 b. When viewing the capacitor chips 20 from the Y-axis direction as shown in FIG. 3A, the lower edges (chip second sides 20 h below) of the first end surfaces 20 a of the capacitor chips 20 can be recognized from the side of the capacitor 10 via the second through holes 36 b.

As shown in FIG. 1, a pair of the upper arm portion 31 a and lower arm portion 31 b holds one capacitor chip 20, and a pair of the upper arm portion 33 a and lower arm portion 33 b holds another one capacitor chip 20. Since a pair of the upper arm portion 31 a and the lower arm portion 31 b (or the upper arm portion 33 a and lower arm portion 33 b) holds one capacitor chip 20, not multiple capacitor chips 20, the first metal terminal 30 can definitely hold each of the capacitor chips 20.

A pair of the upper arm portion 31 a and lower arm portion 31 b does not hold the capacitor chip 20 from both ends of the chip second sides 20 h, which are shorter sides of the first end surface 20 a, but holds the capacitor chip 20 from both ends of the chip first sides 20 g, which are longer sides. This increases distances between the upper arm portions 31 a and 33 a and the lower arm portions 31 b and 33 b, and easily absorbs a vibration of the capacitor chips 20. Thus, the capacitor 10 can favorably prevent an acoustic noise.

Incidentally, a pair of the upper arm portion 31 a and the lower arm portion 31 b holding the capacitor chip 20 may have mutually asymmetry shapes and mutually different lengths in the width direction (lengths in the X-axis direction). Since the lower arm portions 31 b and 33 b extend from the terminal connection part 36 k, the capacitor chips 20 have a short transmission path between the first terminal electrodes 22 and the mount board, compared to when the lower arm portions 31 b and 33 b are connected with the plate body part 36 j.

The mount portion 38 is connected with the terminal second side 36 hb below in the electrode face portion 36. The mount portion 38 extends from the terminal second side 36 hb below toward the capacitor chips 20 (negative side of the Y-axis direction) and is bent approximately vertically to the electrode face portion 36. Incidentally, the top surface of the mount portion 38, which is a surface of the mount portion 38 closer to the capacitor chips 20, preferably has a solder wettability that is lower than a solder wettability of the bottom surface of the mount portion 38 in order to prevent an excessive scattering of a solder used when the capacitor chips 20 are mounted on a board.

The mount portion 38 of the capacitor 10 is mounted on a mount surface, such as a mount board, in a position facing downward as shown in FIG. 1 and FIG. 2. Thus, a height of the capacitor 10 in the Z-axis direction is a height of the capacitor 10 when being mounted. In the capacitor 10, the mount portion 38 is connected with the terminal second side 36 hb on one side of the electrode face portion 36, and the upper arm portions 31 a and 33 a are connected with the terminal second side 36 ha on the other side of the electrode face portion 36. Thus, the capacitor 10 has no unnecessary part of the length in the Z-axis direction and is advantageous in reducing its height.

Since the mount portion 38 is connected with the terminal second side 36 hb on one side of the electrode face portion 36, the capacitor 10 can have a small projected area in the Z-axis direction and have a small mount area, compared to prior arts where the mount portion 38 is connected with the terminal first sides 36 g of the electrode face portion 36. Since the third and fourth side surfaces 20 e and 20 f having small areas of the first to fourth side surfaces 20 c to 20 f of the capacitor chips 20 are arranged in parallel to the mount surface, the capacitor 10 can have a small mount area even if the capacitor chips 20 are not overlapped with each other in the height direction.

As shown in FIG. 1 and FIG. 2, the second metal terminal 40 has an electrode face portion 46, a plurality of pairs of engagement arm portions 41 a, 41 b, and 43 a, and a mount portion 48. The electrode face portion 46 faces the second terminal electrodes 24. The engagement arm portions 41 a, 41 b, 43 a, and 43 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 48 extends from the electrode face portion 46 toward the capacitor chips 20 and is at least partially approximately vertical to the electrode face portion 46.

As is the case with the electrode face portion 36 of the first metal terminal 30, the electrode face portion 46 of the second metal terminal 40 has a pair of terminal first sides 46 g approximately parallel to the chip first sides 20 g and a terminal second side 46 ha approximately parallel to the chip second sides 20 h. The electrode face portion 46 is provided with protrusions (not illustrated), first through holes (not illustrated), second through holes (not illustrated), and slits 46 d (see FIG. 6), all of which are similar to those of the protrusions 36 a, the first through holes 36 b, the second through holes 36 c, and the slits 36 d formed on the electrode face portion 36.

As shown in FIG. 1, the second metal terminal 40 is arranged symmetrically to the first metal terminal 30, and is different from the first metal terminal 30 in arrangement against the capacitor chips 20. The second metal terminal 40 is, however, different from the first metal terminal 30 only in arrangement against the capacitor chips 20 and has a similar shape to the first metal terminal 30. Thus, the second metal terminal 40 are not described in detail.

The first metal terminal 30 and the second metal terminal 40 are composed of any conductive metal material, such as iron, nickel, copper, silver, and an alloy thereof. In particular, the first and second metal terminals 30 and 40 are preferably composed of phosphor bronze in consideration of restraining resistivity of the first and second metal terminals 30 and 40 and reducing ESR of the capacitor 10.

Hereinafter, a manufacturing method of the capacitor 10 is described.

Manufacturing Method of Multilayer Capacitor Chip 20

In a manufacture of the multilayer capacitor chip 20, a laminated body is prepared by laminating green sheets (to be the dielectric layers 28 after firing) with electrode patterns to be the internal electrode layers 26 after firing, and a capacitor element body is obtained by pressurizing and firing the obtained laminated body. Moreover, the first and second terminal electrodes 22 and 24 are formed on the capacitor element body by baking and plating a terminal electrode paint, and the capacitor chip 20 is thereby obtained.

A green sheet paint and an internal electrode layer paint, which are raw materials of the laminated body, a raw material of the terminal electrodes, firing conditions of the laminated body and the electrodes, and the like are not limited, and can be determined with reference to known manufacturing methods or so. In the present embodiment, ceramic green sheets whose main component is barium titanate are used as a dielectric material. In the terminal electrodes, a Cu paste is immersed and baked to form a baked layer, and a Ni plating treatment and a Sn plating treatment are conducted, whereby Cu baked layer/Ni plating layer/Sn plating layer is formed.

Manufacturing Method of Metal Terminals 30 and 40

In a manufacture of the first metal terminal 30, a metal plate is firstly prepared. The metal plate is composed of any conductive metal material, such as iron, nickel, copper, silver, and an alloy thereof. Next, the metal plate is machined to form intermediate members having shapes of the engagement arm portions 31 a to 33 b, the electrode face portion 36, the mount portion 38, and the like.

Next, a metal film is formed by plating on the surfaces of the intermediate members formed by machining, and the first metal terminal 30 is obtained. Any material, such as Ni, Sn, and Cu, is used for the plating. In the plating treatment, a resist treatment against a top surface of the mount portion 38 can prevent the plating from attaching to the top surface of the mount portion 38. This makes it possible to generate a difference in solder wettability between the top surface and the bottom surface of the mount portion 38. Incidentally, a similar difference can be generated by conducting a plating treatment against the entire intermediate members for formation of a metal film and removing only the metal film formed on the top surface of the mount portion 38 using a laser exfoliation or so.

Incidentally, in the manufacture of the first metal terminals 30, a plurality of the first metal terminals 30 may be formed in a state of being connected with each other from a metal plate continuously formed in belt shape. The plurality of the first metal terminals 30 is cut into pieces before or after being connected with the capacitor chip 20. The second metal terminal 40 is manufactured in a similar manner to the first metal terminal 30.

Assembly of Capacitor 10

Two capacitor chips 20 obtained in the above-mentioned manner are prepared and held so that the second side surface 20 d and the first side surface 20 c are arranged to touch each other. Then, a rear surface of the first metal terminal 30 faces the end surfaces of the first terminal electrodes 22 in the Y-axis direction, and the second metal terminal 40 faces the end surfaces of the second terminal electrodes 24 in the Y-axis direction.

At this time, the connection member 50 (see FIG. 2), such as a solder, is applied to the initial application regions 50 c shown in FIG. 1 and FIG. 3A on the end surfaces of the first terminal electrodes 22 in the Y-axis direction or on the rear surface of the first metal terminal 30. The connection member 50 (see FIG. 2), such as a solder, is similarly applied at positions corresponding with the initial application regions 50 c shown in FIG. 1 and FIG. 3A on the end surfaces of the second terminal electrodes 24 in the Y-axis direction or on the rear surface of the second metal terminal 40.

Thereafter, the joint region 50 a is formed in such a manner that the connection member 50 applied on the initial application regions 50 c spreads out by pushing a heating element (not illustrated) from the external surface of the electrode face portion 36 (the same applies to the electrode face portion 46) toward the end surfaces of the chips 20. The non-joint region 50 b is a region where the connection member 50 is not spread out. This allows the first and second metal terminals 30 and 40 to be electrically and mechanically connected with the first and second terminal electrodes 22 and 24 of the capacitor chips 20. Then, the capacitor 10 is obtained.

In the capacitor 10 obtained in this way, a height direction (Z-axis direction) of the capacitor 10 is identical to directions of the chip first sides 20 g, which are loger sides of the capacitor chips 20, and the mount portions 38 and 48 are formed by being bent from the terminal second side 36 hb toward below the capacitor chips 20. Thus, the capacitor 10 has a small projected area in the height direction of the capacitor 10 (see FIG. 4 and FIG. 5), and can have a small mount area.

In the capacitor 10, where a plurality of the capacitor chips 20 is arranged side by side in the parallel direction to the mount surface, for example, only one capacitor chip 20 is held along an engagement direction (Z-axis direction) between a pair of the engagement arm portions 31 a and 31 b. Thus, the capacitor 10 has a high connection reliability between the capacitor chip 20 and the metal terminals 30 and 40, and has a high reliability for impact and vibration.

Moreover, since a plurality of the capacitor chips 20 is arranged and laminated in the parallel direction to the mount surface, the capacitor 10 has a short transmission path and can achieve a low ESL. Since the capacitor chips 20 are held vertically to the lamination direction of the capacitor chips 20, the first and second metal terminals 30 and 40 can hold the capacitor chips 20 without any problems even if the length L2 of the chip second side 20 h of the capacitor chips 20 varies due to change in the lamination number of the capacitor chips 20 to be held. Since the first and second metal terminals 30 and 40 can hold the capacitor chips 20 having various lamination numbers, the capacitor 10 can flexibly respond to design change.

In the capacitor 10, the upper arm portions 31 a and 33 a and the lower arm portions 31 b and 33 b sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g, which are longer sides of the first end surfaces 20 a of the capacitor chips 20. Thus, the first and second metal terminals 30 and 40 can effectively demonstrate a restraint effect on stress, prevent a transmission of vibration from the capacitor chips 20 to the mount board, and prevent an acoustic noise.

In particular, since the lower arm portions 31 b and 33 b are formed by being bent from the lower opening edges of the second through holes 36 c, the lower arm portions 31 b and 33 b supporting the capacitor chips 20 and the electrode face portions 36 and 46 supporting the lower arm portions 31 b and 33 b have elastically deformable shapes. Thus, the first and second metal terminals 30 and 40 can effectively demonstrate a restraint effect on a stress generated in the capacitor 10 and a vibration absorption effect.

Since the lower arm portions 31 b and 33 b are formed on the lower opening ends of the second through holes 36 c while being bent, the capacitor 10 can arrange the lower arm portions 31 b and 33 b at overlapped positions with the mount portion 38 when viewed from the vertical direction (Z-axis direction) to the mount surface (see FIG. 2 and FIG. 5). Thus, the capacitor 10 can have a wide mount portion 38 and is advantageous in downsizing.

Since the first through holes 36 b are formed, a connection state between the first and second metal terminal portions 30 and 40 and the chip capacitors 20 can be easily recognized from outside, and the ceramic capacitor 10 can thereby have a reduced quality dispersion and an improved non-defective product ratio.

In the capacitor 10 according to the present embodiment, a pair of the engagement arm portions (holding portions with elasticity) 31 a, 31 b, 33 a, and 33 b (the same applies to 41 a, 41 b, 43 a, and 43 b) of the metal terminal 30 (the same applies to the metal terminal 40) particularly sandwich and hold the chips 20 from both sides in the Z-axis direction. In addition, the connection member 50 (see FIG. 2), such as a solder, connects between the metal terminals 30 and 40 and the chips 20 within a predetermined range of the joint regions 50 a, and the chips 20 and the metal terminals 30 and 40 can be joined definitely and firmly.

The non-joint region 50 b, which does not connect between the electrode face portion 36 (46) and the end surfaces of the terminal electrode 22 (24), is formed between the peripheries of the joint regions 50 a and the engagement arm portions 31 a, 31 b, 33 a, and 33 b (the same applies to 41 a, 41 b, 43 a, and 43 b). In the non-joint region 50 b, the electrode face portion 36 (46) of the metal terminals 30 (40) can be freely elastically deformed without being disturbed, and stress is reduced. This favorably maintains an elastic property of the engagement arm portions 31 a, 31 b, 33 a, and 33 b (41 a, 41 b, 43 a, and 43 b) continuing to the non-joint region 50 b, and the chips 20 can be favorably held between a pair of the engagement arm portions 31 a and 31 b and between a pair of the engagement arm portions 33 a and 33 b. In addition, the metal terminal 30 (40) is easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

A total area of the non-joint region 50 b is larger than 3/10 of a total area of the joint regions 50 a and is within a predetermined range between the electrode face portion 36 (46) and the terminal electrodes 22 (24). This structure improves the effects of the present embodiment.

In the non-joint region 50 b, a space whose thickness is approximately equal to a thickness of the connection member 50 exists between the electrode face portion 36 (46) and the end surfaces of the terminal electrodes 22 (24). The space enables the electrode face portion 36 (46) of the non-joint region 50 b to be freely elastically deformed without any disturbance from the metal terminal 30 (40).

Moreover, as shown in FIG. 3A, the end surfaces of the terminal electrodes 22 (24) of a plurality of the chips 20 may be joined side by side with the electrode face portion 36 (46) in a plurality of the joint regions 50 a, and the non-joint region 50 b is formed between the joint regions 50 a adjacent to each other. In this structure, a pair of the metal terminals 30 and 40 can easily connect a plurality of the chips 20, and an acoustic noise phenomenon can be prevented due to the existence of the non-joint region 50 b existing between the chips 20.

Moreover, in the present embodiment, the electrode face portion 36 (46) is provided with the second through holes 36 c, which go through the front and back surfaces of the electrode face portion 36 (46), in the non-joint region 50 b. The arm portions 31 a and 33 b (41 b and 43 b) extend from the opening peripheries of the second through holes 36 c. Since the second through holes 36 c are formed, the non-joint region 50 b can be formed easily, the arm portions 31 a and 33 b (41 b and 43 b) can be formed easily, and the chips 20 are held firmly.

Moreover, in the present embodiment, the protrusions 36 a protruding toward the end surfaces of the terminal electrode 22 (24) are formed on the inner surface of the electrode face portion 36 (46). This structure can easily control the joint regions 50 a of the connection member 50 and a thickness of the joint regions 50 a. In addition, this structure stabilizes the connection of the connection member even if the amount of the connection member is small.

In the present embodiment, no vibration travels from the chips 20 to the metal terminal 30 in the second through holes 36 c. In particular, a vibration is easily generated in a part of the chips 20 where the internal electrodes 26 are laminated via the dielectric layers due to electrostrictive phenomenon. In the present embodiment, however, the vibration can be prevented from traveling in the second through holes 36 c.

In the present embodiment, as shown in FIG. 2, the non-joint region 50 b, where no connection member 50 exists between the electrode face portion 36 and the end surfaces of the terminal electrodes 22, exists in the non-opening region 36 c 1 of the electrode face portion 36 within the range of the predetermined height L4, which corresponds with the second through holes 36 c shown in FIG. 3A. In the non-joint region 50 b, the electrode face portion 36 of the metal terminal 30 can be freely elastically deformed without being disturbed, and stress is reduced. This favorably maintains an elastic property of the lower arm portions 31 b and 33 b as the holding portions continuing to the non-joint region 50 b, and the chips 20 can be held favorably by the lower arm portions 31 b and 33 b. In addition, the metal terminal 30 can be easily elastically deformed, and an acoustic noise phenomenon can be prevented effectively.

In the present embodiment, as shown in FIG. 3A, a lamination direction (X-axis direction) of the internal electrodes 26 is substantially vertical to a height direction (Z-axis direction) of the electrode face portion 36, and the second through holes 36 c are formed on the electrode face portion 36 so that vicinities of the end portions of the terminal electrodes 22 are exposed to the outside. This structure can prevent an electrostrictive vibration of the internal electrodes 26 from traveling to a mount board (not illustrated) via the metal terminal 30 on the side close to the mount portion 38 connected with the mount board.

In the present embodiment, a length L5 of the internal electrodes 26 corresponding with a part of the terminal electrode 22 exposed by the second through hole 36 c is 1/20 or more of a total length L6 of the internal electrode 26 shown in FIG. 6. This structure improves a prevention effect on an electrostrictive vibration from traveling to the metal terminal 30 in the second through hole 36. Incidentally, a length L5 of the internal electrodes 26 corresponding with a part of the terminal electrode 22 exposed by the second through hole 36 c is preferably ½ or less of a total length L6 of the internal electrode 26. This is for improving a joint strength between the electrode face portion 36 of the metal terminal 30 and the terminal electrode 22 of the chip 20.

In the present embodiment, the lower arm portions 31 b and 33 b are formed on the side of the mount portion of the second through holes 36 c. In this structure, an electrostrictive vibration of the internal electrodes 26 can be prevented from traveling to the metal terminal 30 on the side close to the mount portion 38. The lower arm portions 31 b and 33 b are hard to be affected by the electrostrictive vibration and can securely hold the chips 20.

In the present embodiment, the lower arm portions 31 b and 33 b are formed by being bent from opening peripheries of the second through holes 36 c. In this structure, the second through holes 36 c and the lower arm portions 31 b and 33 b can be formed easily. In this structure, the second through holes 36 c and the lower arm portions 31 b and 33 b are arranged close to each other, and it is possible to more effectively prevent a vibration transmission from the chips 20 to the metal terminal 30 and a vibration transmission from the metal terminal 30 to the mount board.

Second Embodiment

FIG. 7 is a schematic perspective view of a capacitor 100 according to Second Embodiment of the present invention. FIG. 8 to FIG. 11 are respectively a front view, a left side view, a top view, and a bottom view of the capacitor 100. As shown in FIG. 7, the capacitor 100 is similar to the capacitor 10 according to First Embodiment except that the capacitor 100 has three capacitor chips 20 and a different number of first through holes 36 b or so contained in a first metal terminal 130 and a second metal terminal 140. In the description of the capacitor 100, similar parts to the capacitor 10 are provided with similar references to the capacitor 10 and are not described.

As shown in FIG. 7, the capacitor chips 20 contained in the capacitor 100 are similar to the capacitor chips 20 contained in the capacitor 10 shown in FIG. 1. The three capacitor chips 20 contained in the capacitor 100 are arranged so that chip first sides 20 g are vertical to a mount surface as shown in FIG. 8, and that chip second sides 20 h are parallel to a mount surface as shown in FIG. 10. The three capacitor chips 20 contained in the capacitor 100 are arranged in parallel to a mount surface so that the first terminal electrodes 22 of the capacitor chips 20 adjacent to each other are mutually in contact with, and that the second terminal electrodes 24 of the capacitor chips 20 adjacent to each other are mutually in contact with.

The first metal terminal 130 contained in the capacitor 100 has an electrode face portion 136, three pairs of engagement arm portions 31 a, 31 b, 33 a, 33 b, 35 a, and 35 b, and a mount portion 138. The electrode face portion 136 faces the first terminal electrodes 22. The three pairs of engagement arm portions 31 a, 31 b, 33 a, 33 b, 35 a, and 35 b hold the capacitor chips 20. The mount portion 138 is bent vertically from a terminal second side 136 hb of the electrode face portion 136 toward the capacitor chips 20. The electrode face portion 136 has a substantially rectangular flat shape, and has a pair of terminal first sides 136 g approximately parallel to the chip first sides 20 g and a pair of terminal second sides 136 ha and 136 hb approximately parallel to the chip second sides 20 h.

As is the case with the first metal terminal 30 shown in FIG. 3A, the first metal terminal 130 is provided with the protrusions 36 a, the first through holes 36 b, the second through holes 36 c, and the slits 36 d as shown in FIG. 9. The first metal terminal 130 is, however, provided with three each of the first through holes 36 b, the second through holes 36 c, and the slits 36 d, and each of the first through holes 36 b, the second through holes 36 c, and the slits 36 d corresponds with each of the capacitor chips 20. The first metal terminal 130 is provided with 12 protrusions 36 a in total, and the four protrusions 36 a correspond with each of the capacitor chips 20.

In the first metal terminal 130, as shown in FIG. 10, the upper arm portion 31 a and the lower arm portion 31 b hold one of the capacitor chips 20, the upper arm portion 33 a and the lower arm portion 33 b hold another one of the capacitor chips 20, and the upper arm portion 35 a and the lower arm portion 35 b hold another one of the capacitor chips 20 that is different from the above two capacitor chips 20. The upper arm portions 31 a, 33 a, and 35 a are connected with the terminal second side 136 ha at the upper part of the electrode face portion 136 (positive side of the Z-axis direction), and the lower arm portions 31 b, 33 b, and 35 b are connected with periphery portions of the second through holes 36 c.

As shown in FIG. 8 and FIG. 11, the mount portion 138 of the first metal terminal 130 is connected with the terminal second side 136 hb at the lower part of the electrode face portion 136 (negative side of the Z-axis direction). The mount portion 138 extends from the terminal second side 136 hb below toward the capacitor chips 20 (negative side of the Y-axis direction) and is bent approximately vertically to the electrode face portion 136.

The second metal terminal 140 has an electrode face portion 146, a plurality of pairs of engagement arm portions 41 a, 43 a, and 45 a, and a mount portion 148. The electrode face portion 146 faces the second terminal electrodes 24. The engagement arm portions 41 a, 43 a, and 45 a sandwich and hold the capacitor chips 20 from both ends of the chip first sides 20 g in the Z-axis direction. The mount portion 148 extends from the electrode face portion 146 toward the capacitor chips 20 and are at least partially approximately vertical to the electrode face portion 146.

As is the case with the electrode face portion 36 of the first metal terminal 130, the electrode face portion 146 of the second metal terminal 140 has a pair of terminal first sides 146 g approximately parallel to the chip first side 20 g and a terminal second side 146 ha approximately parallel to the chip second sides 20 h, and the electrode face portion 146 is provided with the protrusions 46 a, first through holes, second through holes, and slits. As shown in FIG. 7, the second metal terminal 140 is arranged symmetrically to the first metal terminal 130 and is different from the first metal terminal 130 in arrangement to the capacitor chips 20. The second metal terminal 140 is, however, different from the first metal terminal 130 only in arrangement and has a similar shape to the first metal terminal 130. Thus, the second metal terminal 140 is not described in detail.

The capacitor 100 according to Second Embodiment has similar effects to those of the capacitor 10 according to First Embodiment. Incidentally, the number of the upper arm portions 31 a to 35 a, the lower arm portions 31 b to 35 b, the first through holes 36 b, the second through holes 36 c, and the slits 36 d contained in the first metal terminal 130 of the capacitor 100 is the same as the number of the capacitor chips 20 contained in the capacitor 100, but the number of the engagement arm portions or so contained in the capacitor 100 is not limited thereto. For example, the first metal terminal 130 may be provided with twice as many first through holes 36 b as the capacitor chips 20, or may be provided with a single continuous long slit 36 d.

Third Embodiment

FIG. 3C is a left side view showing a capacitor 300 according to Third Embodiment of the present invention. The capacitor 300 according to Second Variation is similar to the capacitor 10 according to First Embodiment except for the shape of slits 336 d formed on first and second metal terminals 330. As shown in FIG. 3C, the first and second metal terminals 330 are provided with a single slit 336 d formed below two second through holes 36 c and continuing in the X-axis direction. The slit 336 d has any shape and number as long as the slit 336 d is formed between lower edges (chip second sides 20 h below) of the capacitor chips 20 facing the first end surfaces 20 a and the terminal second side 36 hb (i.e., terminal connection part 36 k).

Fourth Embodiment

FIG. 3D is a left side view showing a capacitor 400 according to Fourth Embodiment of the present invention. The capacitor 400 according to Fourth Embodiment is similar to the capacitor 10 according to First Embodiment except for the shape of a second through hole 36 c formed on first and second metal terminals 430. As shown in FIG. 3D, the first and second metal terminals 430 are provided with a single second through hole 36 c continuing in the X-axis direction. The electrode face portion 36 is provided with the second through hole 36 c so that a part of the terminal electrodes 22 (a part of lower ends) corresponding with lower ends of the internal electrodes 26 in the Z-axis direction of a plurality of chips 20 adjacent to each other is exposed to the outside.

In this embodiment, a width of the second through hole 36 c in the X-axis direction is preferably smaller than a total width of each chip 20 in the X-axis direction, and is preferably ⅙ to ⅚, more preferably ⅓ to ⅔, of a total width of each chip 20 in the X-axis direction.

Fifth Embodiment

FIG. 3E is a left side view showing a capacitor 500 according to Fifth Embodiment of the present invention. The capacitor 500 according to Fifth Embodiment is similar to the capacitor 10 according to First Embodiment except that notches (opening portions) 536 c are formed on first and second metal terminals 530 instead of the second through holes 36 c. As shown in FIG. 3E, the first and second metal terminals 530 are provided with a non-opening region 36 c 1 in the middle of the X-axis direction, and each of the notches 536 c is formed on both sides of the non-opening region 36 c 1. The notches 536 c are formed on the electrode face portion 36 so that a part of the terminal electrodes 22 (a part of lower ends) corresponding with lower ends of the internal electrode layers 26 in the Z-axis direction is exposed to the outside.

Sixth Embodiment

FIG. 3F is a left side view showing a capacitor 600 according to Sixth Embodiment of the present invention. The capacitor 600 according to Sixth Embodiment is similar to the capacitor 10 according to First Embodiment except that only a single capacitor chip 20 is connected with first and second metal terminals 630. The present embodiment also demonstrates effects similar to those of First Embodiment.

Other Embodiments

Incidentally, the present invention is not limited to the above-mentioned embodiments and can be variously changed within the scope of the present invention.

For example, the metal terminals 30, 130, 40, 140, 330, 430, 530, and 630 are provided with the protrusions 36 a, the first through holes 36 b, and the slits 36 d (or 336 d) as necessary, but the metal terminal of the present invention is not limited to the metal terminals 30, 130, 40, 140, 330, 430, 530, and 630 and also includes a variation where one or more of the protrusions 36 a, the first through holes 36 b, and the slits 36 d (or 336 d) are not formed. A pair of the arm portions (e.g., 31 a and 31 b) is formed in the Z-axis direction in the above-mentioned embodiments, but one of the arm portions (e.g., 31 a, 33 a, 35 a, 41 a, 43 a, and 45 a) positioned at the upper part of the Z-axis direction may not exist, and only the other of the arm portions (e.g., 31 b, 33 b, 35 b, 41 b, and 43 b) may exist. Instead, the arm portions (e.g., 31 a and 31 b) on both sides in the Z-axis direction may not exist, and the metal terminals 30, 130, 40, 140, 330, 430, 530, and 630 with the opening portion 36 c may be connected with the terminal electrode 22 (24) of the chip 20 by only the joint region 50 a.

In the present invention, the number of chips owned by the electronic device may be singular or any plural. For example, the metal terminals 130 and 140 hold five capacitor chips 20 in the X-axis direction in the capacitor 500 shown in FIG. 12. In the capacitor 600 shown in FIG. 14, the metal terminals 130 and 140 hold 10 capacitor chips 20 in the X-axis direction.

NUMERICAL REFERENCES

-   10, 100, 200, 300, 400, 500, 600, 700, 800 . . . capacitor -   20 . . . capacitor chip -   20 a . . . first end surface -   20 b . . . second end surface -   20 c . . . first side surface -   20 d . . . second side surface -   20 e . . . third side surface -   20 f . . . fourth side surface -   20 g . . . chip first side -   20 h . . . chip second side -   20 j . . . chip third side -   22 . . . first terminal electrode -   24 . . . second terminal electrode -   26 . . . internal electrode layer -   28 . . . dielectric layer -   30, 130, 40, 140, 330, 430, 530 . . . metal terminal -   31 a, 33 a, 35 a, 41 a, 43 a, 45 a . . . upper arm portion (holding     portion) -   31 b, 33 b, 35 b, 41 b, 43 b . . . lower arm portion (holding     portion) -   36, 136, 46, 146 . . . electrode face portion -   36 a, 46 a . . . protrusion -   36 b . . . first through hole -   36 c . . . second through hole -   36 c 1 . . . non-opening region -   36 d, 46 d . . . slit -   36 g . . . terminal first side -   36 ha, 36 hb . . . terminal second side -   38, 138, 48, 148 . . . mount portion -   50 . . . connection member -   50 a . . . joint region -   50 b . . . non-joint region -   50 c . . . initial application region 

1. An electronic device comprising: a chip component having an element body where internal electrodes are laminated inside and a terminal electrode formed outside the element body and connected with end parts of the internal electrodes; and a metal terminal connected with the terminal electrode of the chip component, wherein the metal terminal comprises: an electrode face portion arranged correspondingly with an end surface of the terminal electrode; and a mount portion mounted on a mount surface, and the electrode face portion is provided with an opening portion so that a part of the terminal electrode corresponding with at least a part of the internal electrodes is exposed to the outside.
 2. The electronic device according to claim 1, wherein the terminal electrode of the chip component is connected with the metal terminal so that plane directions of the internal electrodes are arranged substantially vertically to the mount surface.
 3. The electronic device according to claim 1, wherein the metal terminal further comprises a holding portion holing the chip component, a connection member connecting between the electrode face portion and the end surface of the terminal electrode exists therebetween in a joint region within a first predetermined height, the electrode face portion is provided with the opening portion between a periphery portion of the joint region and the mount portion, and a non-joint region where the connection member does not exist between the electrode face portion and the end surface of the terminal electrode exists in a non-opening region of the electrode face portion within a second predetermined height corresponding with the opening portion.
 4. The electronic device according to claim 1, wherein the electrode face portion is provided with the opening portion so that a vicinity of an end part of the terminal electrode is exposed to the outside.
 5. The electronic device according to claim 1, wherein a length of a part of the internal electrodes corresponding with a part of the terminal electrode exposed by the opening portion is 1/20 or more of a total length of the internal electrode.
 6. The electronic device according to claim 3, wherein a space whose thickness is substantially equal to a thickness of the connection member exists between the electrode face portion and the end surface of the terminal electrode in the non-joint region.
 7. The electronic device according to claim 3, wherein end surfaces of terminal electrodes of a plurality of the chip components are joined side by side with the electrode face portion by a plurality of joint regions, and the non-joint region is also formed between the joint regions adjacent to each other.
 8. The electronic device according to claim 3, wherein the holding portion is formed on the side of the mount portion of the opening portion.
 9. The electronic device according to claim 3, wherein the holding portion is formed by being bent from an opening periphery of the opening portion. 